Spreader stoker



Dec. 4, 1945. w. L V 2,390,155

SPREADER STOKER Filed July 23, 1943 2 Sheets-Sheet 1. \r\\ INVENTOR Wilbur Kass/er BY w ATTORNEY Dec. 4, 1945.

W. KESSLER SPREADER YSTOKER 2 Sheets-Sheet 2 Filed July 23, 1945 INVENTOR I W/Zbur Kass/er BY W. Va @M ATTORNEY Patented Dec. 4, 1945 SPREADER STOKER Wilbur Kessler, Newtown Square, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 23, 1943, Serial No. 495,807

Claims.

This invention relates to stokers, more particularly to stokers of the spreader or sprinkle type, and has for an object to provide improved apparatus of this character.

To the best of applicants knowledge, most in-. dustrial spreader-feed stokers on the market fail to provide uniformdistribution of fuel laterally of the grate surface. The bed of fuel deposited thereon is generally thin along the lateral edges of the area .of distribution of each feeder unit; and, where a plurality of suchv units are employed in a furnace, the space, on the grates between the feeders is nearly empty of fuel adjacent the furnace front wall, this nearly empty area being triangular in shape with its base at the front wall and having an altitude longitudinally of the grate of from 2 to 3' feet.

Large quantities of excess, air are admitted to the combustion chamber through the. near empty spaces on the grates and the thin portions of the fuel bed at, the lateral edges. As a result, either a high furnac or a high degree of turbulence is necessary to make this excess air useful for combustion,

Therefore, another object of the invention is to provide a spreader fuel feeder for stokers which will provide more uniform lateral distribution of the fuel laterally of the furnace than has been obtainable heretofore.

A further object of the invention is the provision of a fuel-feeding mechanism for delivering a greater quantity of fuel to the end portions of a fuel-impelling device, than is delivered to the inter-mediate portion thereof.

These and other objects are effected by the invention as will be apparent from the, following description and claims taken in accordance with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a plan view of a furnace fed by a pair of conventional spreader stokers, and illustrating the problem which applicant is solving;

Fig. 2 is an enlarged fragmentary view of one form of applicants invention;

Fig. 3 is a longitudinal sectional view taken along the line III--III of Fig. 2, looking in the direction indicated by the arrows;

Fig. 4 is a transverse sectional view taken along the line IVIV of Fig. 2, looking in the direction indicated by the arrows;

Fig. 5 is a sectional view of a further modification of the invention;

Fig. 6 is a sectional view taken along the line VIVI of Fig. 5, looking in the direction indicated by the arrows;

Figs. 7 and 8 are sectional views taken along the lines VIIVII and VIIIVII I, respectively, of Fig. 6, looking in the directions indicated by the arrows;

Fig. 9 is a View similar to Fig. 6, but showing another form of the invention; and

Figs, 10 and 11 are sectional views taken along the lines X-X and XI of Fig. 9, lookin in the directions indicated by the arrows.

Referring now to the drawings more in detail, with particular reference to Fig. 1, there is. shown a furnace l0, comprising a front wall 1!, side walls l2, and a rear wall 13, the front Wall I! having a pair of openings l4 therein, through which fuel is fed by the spreader units I5 to the grate structure 16 forming the bottom Of the furnace combustion chamber. In this figure, the numeral 18 indicates the fuel bed as normally deposited upon the grate surface by the conventional industrial spreader stoker units now on the market. The lateral areas of relatively thin fuel deposits are indicated by the reference character l9, while 20 indicates the portions of the grate surface which are nearly empty of fuel and through which large quantities of excess air pass from the plenum chamber below the grate structure, to the combustion chamber thereabove.

In order to make up for the deficiency of fuel along the lateral portions of the fuel deposits upon the grate surface, it is proposed to feed to the edge or end portions of the rotary impeller of the spreader units, a greater quantity" of fuel than is delivered to the intermediate portions of the impellers, and Figs. 2, 3 and 4 illustrate onev form of apparatus for providing this additional supply of fuel to the end portions of the impeller.

Referringnow to Figs. 2, 3 and 4;, fuel is fed from the hopper 22, by a ram member rearwardly over the reciprocal spill plate 24 to the rotary impeller 25, the latter preferably comprising a hollow body portion 25, to which air may be supplied under pressure for emission through openings 2'! in .the body portion, to sweep the fuel-contacting surfaces of the impeller blades 28.

The reciprocal spill plate 24 has motionimparted thereto by linkage of any desired arrangement, and herein illustrated as links and 3|, the former being connected to the spill plate and the latter to an eccentric arm 32, fixedly secured to the vertical shaft 33 mounted in the lower and upper supports 34 and 35, respectively, carried by th ram box structure 36. The upper end of the shaft 33 is provided with an eccentric arm 38, having its outer or free end pivotally connected to a transversely-extending bar or rod 39, adapted to be reciprocated by any suitable means (not shown).

The vertical shaft 33 also carries an eccentric or crankarm 40, connected by rearwardly-extending link 4| and vertical pivot pin 42 to the ram structure 23, whereby reciprocatory motion is imparted to the latter. As best shown in Fig. 2, the ram 23' has a working or pushing face which varies in height, and therefore in efiective area per unit of length, the central or intermediate portion 44 being relatively low compared to the height of the end portions 45, with the result that reciprocation of the ram 23 provides for delivery of a greater quantity of fuel per unit length of the ram face, to the corresponding end portions of the impeller 25, than to the intermediate portion of the latter.

In Figs. 5, 6, 7 and 8, there is illustrated an arrangement where fuel is fed from the hopper 65 over the spill plate 66, to the rotary impeller 61, by a measuring drum or roll 68. In this construction, the hub or core 10 of the drum or roll 68 is of uniform diameter throughout its length, but the blades or vanes thereof are of greater effective length at their end portions ll than at their intermediate portion 12, with the result that the portions H, at the ends, feed a relatively larger amount of fuel from the hopper to the end portions of the impeller, than is led to the intermediate portions of the impeller by the shorter intermediate portion 12 of the blades or vanes on the roll or drum 68.

The arrangement of Figs. 9, 10 and 11 differs from that of Figs, 5 to 8, in that the radial extent of the blades 15 remains uniform throughout the length of the measuring roll or drum, but the core or hub thereof has its end portions 16 formed of reduced diameter relative to the intermediate portion 1! thereof, with the result that a larger amount of fuel is delivered by the end portions than by the intermediate portion.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is, not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. In a stoker, fuel-feeding mechanism comprising a hopper; fuel-impelling means; and a reciprocal ram adapted to push fuel from the hopper to the impelling means, said ram having a fuel-engaging face disposed in a plane substantially transverse to the direction of its reciprocation, and the end portions of said fuel-engaging face being of greater height than the intermediate portion thereof,

2. In a stoker, fuel-feeding mechanism comprising a hopper; fuel-impelling means; and a feeder roll for delivering fuel from the hopper to the fuel-impelling means, said feeder roll comprising a central axial core and a plurality of blade members extending radially therefrom and providing fuel-receiving pockets of greater capacity at the end portions of the roll than at the central portion thereof, said feeder-roll core being of substantially uniform diameter and the reater capacity of the end portions of the fuelreceiving pockets being provided by greater'radial extension of the pocket-forming blade members at the end portions of the roll.

3. In a stoker; a fuel impeller rotatable about a horizontal axis extending transversely of the direction of fuel feed; and means for delivering fuel to said impeller, said means having a fuelmoving surface lying in a plane substantially parallel to the axis of rotation of the impeller and being of a width approximately equal to the width of the impeller, the height of said surface being greater at the end portions than at the intermediate portion thereof, whereby a greater volume of fuel per unit of width is delivered to the end portions of the impeller than is delivered to the intermediate portion thereof.

4. In a stoker, fuel-impelling means and means for feeding fuel thereto, said feeding means having fuel-engaging surfaces extending substantially the width of the impelling means, said fuel-engaging surface comprising an intermediate section of a predetermined area per unit of width and adapted to deliver fuel to the corresponding intermediate section of the impelling means, and end sections at each side of the intermediate section of greater area per unit of width than the intermediate section and adapted to deliver to the corresponding end portions of the impelling means a greater volume of fuel per unit of width than is delivered to the intermediate section of the impelling means.

5. In a stoker, fuel-feeding mechanism comprising a hopper; fuel-impelling means; and a I feeder roll for delivering fuel from the hopper to the impelling means, said feeder roll comprising a central axial core and a plurality of blade members extending radially therefrom and providing fuel-receiving pockets of greater capacity at the end portions of the roll than at the central portion thereof, the pocket-forming blade members having their outer edges substantially parallel to the axis of rotation of the feeder roll, and the greater capacity of the end portions of the fuel-receiving pockets resulting from lesser diameter of the core at the end portions than at the intermediate portion.

WILBUR KESSLER. 

